the fan of my iMac runs too loud - Can you help determine why it over heats?

If the fans in your device run fast even when it isn't experiencing heavy usage and is properly ventilated, follow the steps for your device:

• On an Intel-based Mac: Reset the System Management Controller (SMC)
• On a Mac computer with Apple silicon: Close and open the lid on your laptop, or restart your computer.

Click on this link to read about fans and fan noise in your Apple product --> About fans and fan noise in your Apple product - Apple Support